What is lidar?Lidar (light detection and ranging) is a new tool that can provide very precise, accurate, and high-resolution images of the surface of the earth, vegetation, and the built environment.

Airborne lidar uses a laser range finder mounted in a precisely navigated aircraft to scan the earth's surface at very high rates and collect very dense clouds of X-Y-Z coordinates. Lidar data that define the ground, vegetation and man-made structures are useful for anyone wanting to know the shape of the land surface or of the vegetation and buildings on the land. (Learn more in the "Seeing Landslides with Lidar" Cascadia issue [6 MB PDF] or or view a presentation [Powerpoint file (12 MB) or Flash Player movie] that explains lidar and the OLC in detail.)

The Oregon Department of Geology and Mineral Industries (DOGAMI) has been involved in pilot efforts to collect high-resolution lidar in Oregon since 2003. In 2006-2007 we were successful in forming the Portland Lidar Consortium, which brought together 17 agencies ranging from the USGS to the City of Silverton to acquire 2200 square miles of seamless, high-quality public domain lidar data (current PLC status - May 27, 2009 [461 KB PDF]). Among the many benefits of the consortium approach are that large swaths of lidar data can be collected seamlessly, costs per unit area to collect the data are greatly reduced, expert quality assurance and quality control are uniformly applied to the data, statewide standardization of data can be assured, and small jurisdictions can benefit from the acquisition of lidar data at a greatly reduced cost when compared to the cost if jurisdictions acted independently.

Comparison of lidar-based digital elevation model (DEM) map on the left with conventional orthophoto on the right. Browse available Portland-area imagery here.

In 2007 the Oregon 74th Legislative Assembly directed DOGAMI to extend lidar collection efforts throughout the state. Legislators approved the consortium model for data collection and data sharing, and provided modest seed money. The ultimate goal is to provide high-quality lidar coverage for the entire state. To achieve this goal DOGAMI has formed the Oregon Lidar Consortium (OLC), which will develop cooperative agreements for the collection of high-quality lidar that benefits the public at large, the business community, and agencies at all levels of government.

In winter 2007 and spring 2008 DOGAMI developed data specifications and selected a vendor (Watershed Sciences Inc., Corvallis, Oregon) through a national competitive bidding process. During this time we also developed several funding partnerships for data collection blocks. Initially, we identified our area of primary interest as the inhabited portions of western Oregon (see map), but we welcome partners with funding for interests outside of that area. We have developed several partnerships that includes areas outside the original target, where partners are willing to pay the full cost of data acquisition. As of October of 2009, the OLC has 11 data acquisition blocks under contract (PDF map of current active areas) and is finalizing the details of funding partnerships for other areas. The cost for data acquisition depends on the size of the area and includes contract management and quality control by DOGAMI.

The basic OLC strategy (outlined in detail in the OLC Business Plan) for developing data acquisition areas is to start with a local funding partner and work to enlarge that area by finding additional partners and adding OLC funds to link areas together into large contiguous blocks.

What software do I need to use lidar data?
For rasters, users need GIS software that can read georeferenced rasters in .adf format (Esri grid) such as ArcGIS, IMAGINE, GeoMedia, etc. QGIS is an open source GIS software option that will support rasters. If the data are downloaded from a third party such as OpenTopography the data come in a variety of formats such as TIF, JPEG, IMAGINE, or Esri grid.

What ways are there to view lidar data?
Lidar can be viewed as either mass points or a raster. The best method to view mass points (i.e., LAS files) is through a 3D point viewer, for example, the free U.S. Forest Service visualization system Fusion. Raster formatted data can be viewed as a digital elevation model (DEM) using a color ramp to expose variations in elevation. Many users create hillshades or slope rasters from the DEMs using GIS software. These derivative products allow for better visualization of surface features.

Can I view lidar data in CAD software?Yes, both AutoCAD Civil 3D and Bentley Microstation support import of raster and LAS point data. It should be noted that LAS point datasets are typically very large and might operate slowly. Additionally, raster imports typically require changing settings. For instance, AutoCAD Civil 3D requires the user to specify ".adf" file format before the file can be viewed.

Can contours be created from lidar data?
Yes. Contours can be derived from lidar rasters using GIS software.

DOGAMI OLC clients receive their data deliverables as per the arrangements of their intergovernmental agreements. All data acquired by OLC will be eventually available in the public domain and made available through our Nature of the Northwest Information Center. Other parties, including the public, will be able to purchase combinations of data types on appropriate media. The data will be organized on a spatial grid, similar to that used for topographic maps. Unit prices are being determined. At this time DOGAMI anticipates that this data available for purchase will include the bare earth and all-returns digital elevation models, intensity images (GeoTiff format), and perhaps the original “point cloud” data. In addition, certain federal agency websites will host the point cloud data where it may be downloaded by interested parties. Read the DOGAMI Lidar Data Distribution Policy (PDF) for details.